Abstract [en]

During viewing of interactive branched video, users are asked to make viewing choices that impact the storyline of the video playback. This type of video puts the users in control of their viewing experiences and provides content creators with great flexibility how to personalize the viewing experience of individual viewers. However, in contrast to with traditional video, where the use of a playback bar is default for most - if not all - players, there currently does not exist any generic playback bar for branched video that helps visualize the upcoming branch choices. Instead, most branched video implementations are typically custom-made on a per-video basis (e.g., see custom-made Netflix and BBC movies) and do not use a playback bar. As an important step towards addressing this void, we present the first branched video player with a generalized playback bar that visualizes the tree-like video structure and the buffer levels of the different branches. The player is implemented in dash.js and is made public with this publication, is the first of its kind, and allows both the playback bar and the presentation of branch choices to be customized with regards to visual appearance, functionality, and the content itself. Furthermore, the design is generic (making it applicable to any video) and allows content creators to easily create large numbers of branched movies using a simple metafile format. Finally, and most importantly, we perform a three-phase user study in which we evaluate the playback bar, compare with alternative designs, and other branch-related features. The user study highlights the value of a branched video playback bar, and provides interesting insights into how it and other design customization features may best be integrated into a player.